Luca Moratto

Source Modeling of the Kozani and Arnea 1995 Events with Strong Motion Estimates for the City of Thessaloniki

We first estimate the source parameters related to the two 1995 events near Thessaloniki (Greece): the Kozani (Ms = 6.6) and the Arnea (Ms = 5.8) earthquakes. We use the strong motion waveforms recorded in Northern Greece to retrieve by forward modeling the source characteristics of the two events. Both point-source and finite-source models are used and different 1-D velocity models tested. Due to the absence of absolute timing of most of the recordings, the modeling is limited to fitting the peak acceleration (PA) at different frequencies at the bedrock stations. The best results in terms of PA are obtained with the finite-source models for a two-asperity k-square distribution. The source model for the Kozani event is compatible with the main fault proposed by Hatzfeld et al. [1997]. Given the two source models, we estimate the strong ground motion that would have been recorded due to these two events at different sites within the city of Thessaloniki. We estimate the strong ground motion by convolving the synthetic bedrock signals at the sites with 1-D and 2-D amplification curves obtained for the same sites during previous studies. Our analysis indicates which of the ten sites are the one most prone to strong shaking and confirms that the most crucial source parameter to be considered in ground shaking models is the rupture directivity.